There has been a door trim (a vehicular interior part) including an armrest. The armrest has a rear edge surface including a cutaway groove so that the armrest is easily broken in a collision. If the armrest receives shock in a side collision, a thin portion of the armrest is broken along the cutaway groove and the rear edge surface of the armrest having a box shape is opened widely to have a substantially L-shaped opening. Accordingly, the armrest is easily broken and effectively absorbs the shock.
However, in such a configuration, the rear edge surface of the armrest that is a side wall of the door trim has rigidity that is lower than rigidity of a side wall without having the groove. Therefore, the rigidity of the door trim during a normal usage may be lowered.
In the above configuration, the groove is formed on a surface that is opposite from a design surface of the side wall of the door trim. Therefore, unevenness in gloss may occur on the design surface of the side wall and this may deteriorate the design.